1. Field of the Invention
The invention relates to a process and a device for the exchange of data via a communications channel between a central unit, which processes, stores and provides data, and a data terminal device, whereby application-related queries (query functionalities) with specific query structures corresponding to given applications are sent from the data terminal device to the central unit,
2. Description of Related Art
Data exchanges of this type take place, for example, between the personal computers of various users [sic], who are connected to a data base computer (e.g., a patent data base) via a communications channel embodied as a data network. As a rule, to acquire desired information from the data base, users must formulate their queries in a particular fixed query language predetermined for use with the data base computer in question. In addition, the responses supplied by the data base computer are, like the user queries, transmitted in fixed predetermined structures. In such applications, the data terminal device of the user is usually stationary; however, its geographic location is of no significance.
However, in certain applications, for example, in the field of traffic telematics, the location of the data terminal device is important. For instance, in off-board navigation systems, the traffic computer queried by a user from a vehicle must obtain information on the user""s current location in order to transmit suitable route recommendations or relevant traffic information to the user""s data terminal device. Furthermore, future applications in this field will use existing traffic telematic device technology, without, however, being directly concerned with specific traffic-related information. For example, the user devices for off-board navigation that are installed in vehicles or carried by individuals and that receive information from a central unit via a wireless communications channel are also suitable for responding to queries about, say, hotels in a predetermined area around the current location of the user. In such cases, the central unit that possesses the desired information must know the current user location to be able to select the relevant data. Similarly, other new services could provide information on currently available parking in the vicinity of the user, for example, or could allow drivers to reserve particular parking places. In addition, desired information on points of interest to the user (e.g., sightseeing, museums and restaurants) could be furnished.
Terminal devices for off-board navigation are fundamentally suitable for such services and simply require appropriate modification. For example, to make accessing these services as simple as possible for users, the terminal device should offer a type of screen mask, into which a user can input essential parameters to narrow down his questions. For instance, in the case of a query about hotels, these parameters could include xe2x80x9cmaximum distance from current location of user,xe2x80x9d xe2x80x9chotel category,xe2x80x9d xe2x80x9cavailability of certain facilitiesxe2x80x9d (e.g., tennis courts, swimming pool) and xe2x80x9cnumber of rooms needed.xe2x80x9d Such a screen mask (query structure) with data field designations would have to be stored in the user data terminal device for each service used (query functionality), as would a format for displaying the response transmitted from the queried central unit.
Today, the storage of suitable query structures and the formatting to display responses are usually implemented in data terminal devices by means of software. By loading a new program into a data terminal device, it is possible to expand the scope of usable query functionalities, particularly to include services that did not even exist when the data terminal device was purchased. Despite this basic technical flexibility, however, it would be very expensive to introduce new software for the purpose of making a genuinely mass application accessible to many thousands or even hundreds of thousands of users. According to the current state of the art, for example, interested users would have to be burdened to obtain technical assistance to have such updates installed into their data terminal devices. This procedure would be made even more difficult, as a rule, by the necessity of loading different manufacturer-specific software versions.
The object of the invention is therefore to propose a generic process and device that permit the necessary software in the data terminal device to be adapted to new or modified query functionalities without great expense.
The invention starts from the recognition that data base queries, including queries made via mobile data terminal devices in the framework of information services for traffic telematic applications, always conform to a parameterable operational sequence (query structure). The invention makes it unnecessary to store query structures designed in advance to serve as explicitly predetermined complete program sequences for each application. Instead, for the purpose of defining and storing such specific query structures, the invention provides an application-independent query structure, i.e., a general query structure that, in each specific case, is used with an application-specific parameter set. This general query structure is stored in each data terminal device and in the central unit and remains permanently unchanged. Specific query structures can then be determined in the data terminal device by interpreting the general query structure on the basis of the specific parameter set provided for the application in question.
Compared with the prior art, the invention also clearly simplifies the transmission of responses from the central unit to the data terminal device. Studies have shown that the specific response structures suitable for practically all possible query functionalities can be divided into a few basic patterns. Instead of storing an individual response structure for each individual query functionality in the data terminal device and the central unit, as has been done, it is now possible, according to the invention, to store only a few application-independent response formats in the data terminal device and the central unit, and to then assign each response to one of these formats.
The process according to the invention is thus characterized by the fact that initially, a permanently unchanged application-independent query structure (general query structure) is entered into both the central unit and the data terminal device, as are a small number of permanently unchanged application-independent response formats. The specific query structure needed for each particular application is defined in dependence on the general query structure, and then stored in the central unit in the form of a parameter set. As desired, the user can use his data terminal device to request from the central unit, via the communications channel, a specific query structure not yet stored in his data terminal device. The data terminal device then receives and stores this requested query structure in the form of the parameter set associated with the application in question. To use the application, i.e., to implement a query functionality, the specific query structure for the application is created in the data terminal device by interpreting the general query structure on the basis of the applicable parameter set. This specific query structure is at least partially filled out with suitable values by the user, and is then transmitted as a query to the central unit. The response subsequently transmitted from the central unit to the data terminal device via the communications channel is made available to the user (e.g., via an optical display device) on the basis of a response format stored in the data terminal device and designated in the response itself. Advantageously, the general query structure contains an identification of the particular query functionality, a list of query parameters, and a list of data types of the query parameters. The predetermined predefined response formats, which are stored both in the data terminal device and the central unit, should comprise at least a single data set and a selection list of data sets. The minimum number of predefined response formats is two, while the maximum number is ten, and preferably five. Often, it is helpful to store the specific query structures in the sense of the invention, i.e., the parameter sets, in the data terminal device over a long term. However, this is by no means necessary. It is also possible for the applicable parameter set to be newly transmitted to the data terminal device for each new query. In this case, the method used in the preferred embodiment of the invention can also be used for query functionalities newly entered into the central unit. The data terminal device is equipped, in the framework of the general query structure, with a permanent fundamental query option for requesting the available query functionalities from the central unit. The new query functionalities displayed in response to such a general request by the data terminal device are preferably presented in the form of a list of all currently available query functionalities. By selecting a particular query functionality, it is possible for the data terminal device to request a specific query structure, as needed.
The invention makes it possible to easily accommodate changes in the query structure of existing query functionalities. When a query is made on the basis of a specific query structure that has been stored in the data terminal device but no longer corresponds to the current status, it is possible, according to the invention, for the current version of the specific query structure to be automatically transmitted from the central unit to the data terminal device and stored there in the form of the applicable parameter set. The user can then easily send an updated query to the central unit. In the data terminal device, it is advisable to make the specific query structure visible to the user in the form of an input mask for entering at least some of the parameters of a query. For many applications, it is advantageous to have at least one query parameter filled out automatically by the data terminal device. For example, data describing the current geographic position of the user or data terminal device are particularly suitable for such automatic entry. This is particularly advantageous when a mobile data terminal device is being used, especially in a vehicle. In this case, data is exchanged between the central unit and the data terminal device via a wireless communications connection. Of course, this type of communications channel can also be used in permanently installed data terminal devices. As a rule, however, standard connections via data lines are used in such cases. When wireless communications are used, it is especially advisable to carry out the data exchange in coded form in the framework of cellular mobile telephone communications. The invention can be used with special advantage for applications in which traffic information and/or information on points of interest to tourists is kept in the central unit, and the geographic coordinates of selected interest points are requested by the user via the data terminal device.
Because the general query structure and the predefined application-independent response formats must be permanently stored in the data terminal device, the use of suitable write-protected memories is recommended for this purpose. It is further recommended that the data terminal device be equipped with an input keyboard and an optical display device. Of course, it is also possible to equip the data terminal device with voice output means for providing responses to the user. To permit the automatic transmission of current position data from a data terminal device, especially a mobile data terminal device, to the central unit, the data terminal device must be equipped with or connected to a device for the automatic determination of geographic position.
The essential advantage of the invention is the extraordinarily great flexibility it provides with respect to the modification of existing services and the introduction of new services. These services can therefore be made available to the owners of data terminal devices that were not necessarily designed in advance specifically to use these services. Because only several basic structures need to be stored in each data terminal device, the manufacturer-specific designs (e.g., selection of microprocessor or operating system) of the individual user devices play no role in the implementation of the invention. Users are not obliged to obtain technical assistance to update the software status of their data terminal devices. In addition, the communications expense for transmitting the specific query structures is very low. As a rule, a maximum total field length of 140 bytes is sufficient for one parameter set.